21.2.2 Stored Routines and MySQL Privileges

The ALTER ROUTINE privilege is
needed to alter or drop stored routines. This privilege is
granted automatically to the creator of a routine if
necessary, and dropped from the creator when the routine is
dropped.

The EXECUTE privilege is
required to execute stored routines. However, this privilege
is granted automatically to the creator of a routine if
necessary (and dropped from the creator when the routine is
dropped). Also, the default SQL SECURITY
characteristic for a routine is DEFINER,
which enables users who have access to the database with which
the routine is associated to execute the routine.